/*
 * Copyright (c) 2010, 2011, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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 */

package java.lang;

import java.io.DataInputStream;
import java.io.InputStream;
import java.lang.ref.SoftReference;
import java.util.Arrays;
import java.util.zip.InflaterInputStream;
import java.security.AccessController;
import java.security.PrivilegedAction;

class CharacterName {

 private static SoftReference<byte[]> refStrPool;
 private static int[][] lookup;

 private static synchronized byte[] initNamePool() {
 byte[] strPool = null;
 if (refStrPool != null && (strPool = refStrPool.get()) != null)
 return strPool;
 DataInputStream dis = null;
 try {
 dis = new DataInputStream(new InflaterInputStream(
 AccessController.doPrivileged(new PrivilegedAction<InputStream>()
 {
 public InputStream run() {
 return getClass().getResourceAsStream("uniName.dat");
 }
 })));

 lookup = new int[(Character.MAX_CODE_POINT + 1) >> 8][];
 int total = dis.readInt();
 int cpEnd = dis.readInt();
 byte ba[] = new byte[cpEnd];
 dis.readFully(ba);

 int nameOff = 0;
 int cpOff = 0;
 int cp = 0;
 do {
 int len = ba[cpOff++] & 0xff;
 if (len == 0) {
 len = ba[cpOff++] & 0xff;
 // always big-endian
 cp = ((ba[cpOff++] & 0xff) << 16) |
 ((ba[cpOff++] & 0xff) << 8) |
 ((ba[cpOff++] & 0xff));
 } else {
 cp++;
 }
 int hi = cp >> 8;
 if (lookup[hi] == null) {
 lookup[hi] = new int[0x100];
 }
 lookup[hi][cp&0xff] = (nameOff << 8) | len;
 nameOff += len;
 } while (cpOff < cpEnd);
 strPool = new byte[total - cpEnd];
 dis.readFully(strPool);
 refStrPool = new SoftReference<>(strPool);
 } catch (Exception x) {
 throw new InternalError(x.getMessage(), x);
 } finally {
 try {
 if (dis != null)
 dis.close();
 } catch (Exception xx) {}
 }
 return strPool;
 }

 public static String get(int cp) {
 byte[] strPool = null;
 if (refStrPool == null || (strPool = refStrPool.get()) == null)
 strPool = initNamePool();
 int off = 0;
 if (lookup[cp>>8] == null ||
 (off = lookup[cp>>8][cp&0xff]) == 0)
 return null;
 @SuppressWarnings("deprecation")
 String result = new String(strPool, 0, off >>> 8, off & 0xff); // ASCII
 return result;
 }
}